1. Field of the Invention
The present invention relates to an enclosed scroll compressor for use in refrigerators, air conditioners, and so on.
2. Description of the Related Art
FIG. 5 shows a vertical sectional view of a known scroll compressor. Referring to FIG. 5, in an upper portion of the interior of an enclosed container 101, there are disposed a compression mechanism 102 comprised of a fixed scroll 102a and a gyratory scroll 102b held in mesh with each other, a crankshaft 103 for driving the gyratory scroll 102b, an Oldham's ring 104 as a rotation preventing mechanism for converting the gyratory scroll 102b from rotating movement into gyrating movement, a thrust bearing 105 for supporting the thrust force of the gyratory scroll 102b, and a bearing part 106 comprised of a main bearing 106a and an auxiliary bearing 106b for jointly bearing the thrust bearing 105 and supporting the crankshaft 103. The fixed scroll 102a and the bearing part 106 are fastened together by bolts through a spacer 108. FIG. 6 shows assembled components around an eccentric bearing of the crankshaft in FIG. 5. An eccentric bearing 110 having an oil groove 109 formed therein and a leaf spring 111 are disposed in a hole 103a formed in an upper end of the crankshaft 103. A shaft 107 of the gyratory scroll 102b is inserted to the eccentric bearing 110 so that the gyratory scroll 102b is gyrated with rotation of the crankshaft 103 in the direction indicated by arrow A in FIG. 6. Further, in FIG. 5, a rotor 112a is attached to the crank-shaft 103 and makes up an electric motor 112 in cooperation with a stator 112b fixed to the enclosed container 101 by shrinkage fitting. The rotor 112a and the stator 112b are both disposed below the compression mechanism 102. An oil pump 113 is provided at a lower end of the crankshaft 103, and oil bores 115a, 115b are formed through the crankshaft 103 for introducing lubricating oil 114 pooled at the bottom of the enclosed container 101 from the oil pump 113 to upper sliding portions. The crankshaft 103 is supported by the main bearing 106a and the auxiliary bearing 106b. Attached to the enclosed container 101 are an intake pipe 118 for sucking a coolant through it and a delivery pipe 119 for discharging the coolant through it. These pipes 118, 119 are connected to an evaporator and a condenser (not shown), respectively, thereby constituting a generally known refrigerating cycle.
The oil pump 113 is generally a pump utilizing centrifugal force. The lubricating oil 114 is supplied to the sliding portions of the eccentric bearing 110, the main bearing 106a, the auxiliary bearing 106b, the thrust bearing 105, etc., which are disposed in the upper portion of the container space, under an action of centrifugal force produced by the oil pump 113 and in the oil bores 115a, 115b formed through the crankshaft 103.
In the above-described structure, however, upper spaces of oil paths (i.e., upper portions of the oil bores 115a, 115b and the hole 103a in the upper end of the crankshaft) are closed or left slightly open with respect to the inner space of the enclosed container. When the compressor is stopped, the upper spaces of the oil paths are filled with coolant gas. To start operation of the compressor and supply the lubricating oil to the sliding portions by sucking the oil by the oil pump 113 from that condition, the gas accumulated in the closed spaces of the oil bores 115a, 115b must be expelled out. The force for supplying the oil to the sliding portions is provided by the centrifugal force produced by the oil pump 113 and in the oil bores 115a, 115b. But, with the coolant gas filled in the oil bores 115a, 115b, sufficient centrifugal force cannot be produced. At the beginning of operation of the compressor, therefore, the accumulated gas is expelled out by insufficient force and, only after that, the oil is supplied to the sliding portions. This has raised a problem that supply of the oil to the sliding portions is delayed and a lubricating trouble such as a seizure may occur.